1. Field of the Invention
The present invention relates to a process for producing a highly oriented, partially drawn, untwisted, compact poly(.epsilon.-caproamide) yarn at windup speeds of from 3500 to 6000 meters per minute. More particularly, the invention relates to a process for producing a highly oriented, partially drawn, untwisted, compact poly(.epsilon.-caproamide) yarn which includes the steps of overfeeding the yarn to entangling means and overfeeding the shrinking yarn to the winder. Yarn is "drawn" in the quench stack when produced according to this process and has low residual shrinkage to ultimately produce more stable fabric, has low elongation as compared with ordinary undrawn, as-spun yarn to preclude the necessity for further drawing, and is entangled sufficiently to permit knitting of the yarn without a twisting operation. Yarn so produced can be beamed directly from a spin package to obviate the need for a draw-twisting step.
2. Discussion of Prior Art
The high speed spinning of yarn is known. Such a process involves cooling and solidifying a yarn spun from a spinnerette, lubricating the solidified yarn, causing (optionally) the lubricated yarn to pass sequentially over first and second godet rolls, and then winding up the yarn on a spool or package at speeds of at least 2500 meters per minute. U.S. Pat. Nos. 3,996,324 to Landenberger et al. and 4,049,763 to Mineo et al. disclose high speed spinning processes. Yarn produced by such a process is highly oriented, most of the orientation or "draw-down" occurring immediately below the spinnerette and increasing as the spinning speed increases. Further, yarn so produced has a low residual draw ratio, the residual draw ratio decreasing as the spinning speed increases. Highly oriented yarn possessing a low residual draw ratio is usually draw-twisted to produce a yarn suitable for the many common textile operations, e.g., knitting and weaving. This additional, discontinuous step, contributes greatly to manufacturing costs, so it is highly desirable that it be eliminated. It is also known to interlace or entangle yarn to replace twisting of the yarn (see U.S. Pat. No. 3,110,151 to Bunting, Jr. et al.), to ensure compact yarn with adequate handling characterstics. In U.S. Pat. No. 3,110,151, the interlacing is preferably carried out as an adjunct to one or more of the common textile operations, such as spinning and/or drawing, packaging, etc. and further, is generally accomplished by advancing yarn at controlled tension and with zero net overfeed to the fluid interlacer or interlacers described in the patent. In U.S. Pat. No. 3,978,558 to Pike, entangled or interlaced multifilament yarn is produced according to a process which includes overfeeding the yarn from about 0.1 to about 10 percent into an entangling jet with output speeds of from 125 to 1250 yards per minute. Other patents which may be pertinent to the present invention are U.S. Pat. No. 2,161,354 to Imray, Jr. et al., Canadian Pat. No. 554,150 to Hartley, and British Pat. No. 1,159,556 to Hartmann.